Method of and means for flowing oil wells



May 28, 1935 H. c. oTls 2,002,791

MTOD OF AND y'MEANS FOR FLOWING OIL WELLS Filed July l0, 1953 4Sheets-Sheet l May 28,1935. H. c. ons l 2,002,791

METHOD OF AND MEANS FOR FLOWING OIL WEIIILS Filed July l0, 1933 14Sheets-Sheet 12 #erbe/'f C. Ufff May 28, 1935. H. c; oTls 2,002,791

METHOD OF AND MEANS FOR FLOWING OIL WELLS Filed July 10g 1,933 4Shea-ets-Slflee'rI 3 May Z8, 1935. H* C, 0115 'i 2,002,791

METHOD OF AND MEANS FORFLOWING OIL WELLS Filed July 10,- 1935 4Sheets-Sheet 4 f A 5m l Q /Z/ /o 65V 64" L i y v Q f5- 'gn/vanto@ n j?,Q @5% M Y lforncq.

Patented May 28, 1935 UNITED STATES PATENT oFFicE i METHOD OF AND MEANSFOR FLOWING OIL WELLS Herbert C. Otis, Shreveport, La.

Application July 10, 1933, Serial No. 679,755

25 Claims.

`l However, when the flow is interrupted, the fluid level in the tubingrises and when flowing is to be resumed, a considerablyhigher or kickoffpressure is required to start the flow than yis necessary to maintainit.

Ordinarily, flowing may be maintained at a pressure of approximatelyfrom two hundred to threehundred pounds, whereas a kick-off pres' sureranges from seven hundred to eight hundred pounds. pressing equipment isnecessary in order to build up these pressures and it is obvious,because of the lower flowing pressurethat a large part of the investmentis idle once the flow is started.

The most eilicient flow velocity when employing air or gas underpressure asa flowing or lifting agent, is usually a velocity so low asto` border on that at which slippage of the liquid in the tubing islikely to take place, but fthe possibility of the well loading up andceasing to flow as a result, necessitates a`higher pressure in order'tomaintain flowing. It is the custom to introduce air or gas so rapidlyand in such volume as to preclude the danger of loading up, eventhough/,such velocity is so high as to result in extremely inefcientflowing. i

- One of the objects of the invention is to overcome the foregoingdifficulties and, to provide an improved methodand means whereby a moreor less constant flow will be maintained without the necessity of theuse of kick-off or comparatively high pressures.

A further object of the invention is to provide a method and meanswhereby the flow may be resumed after the well has been shut down,without the use of kiek-pff or high pressures, and

said flow so regulated that the rate of entry ofY the fluid flowing intothe lower portion'of the tubing, or the flowing pressureof the oil andgas mixture or the influent, flowing through the tubing from the swell,will be less tha/n the input or working pressure of the air and gas,thus removing the danger of loading up when flowing at low efficientvelocities. y

Another object of the invention is to provide means for regulating theeffective flowing pres- A considerable investment in air com.

(ci. ros- 232) sures of the lifting or elevating fluids and the influentfluids, whereby a constant and uninterrupted flowing of the influent isapproached, and also whereby the evils which have been before recitedare more or less overcome.

An important object of the invention is to provide a method and meanswhereby the rate of entry of the influent or oil and gas mixture intothe tubing is regulated so that it will be held within the lifting orjelevating capacity of the lifting or elevating fluids; and particularlywhereby the application of the lifting or elevating energy to the columnof fluids in the tub- `ing is constant, while the energy orpressure'of'` together with means for subjecting the valve to thepressure of the lifting fluid, whereby the valve is opened when thepressure of the lifting fluid exceeds the combined overbalancing and'flowing pressures; but lwherein the pressure of the lifting fluid isless than the submergence pressure, but greater than the flowingpressure. Another' object of the invention is to provide a. controlvalve or regulator having differential working surfaces exposed to thesubmergence or bbottom hole pressure of the influent, whereby the valveis seated, together with a working surface exposed to the lifting orelevating pressure, whereby a lifting pressurein excess of thedifferential pressure as applied to the working surface of the valvewill unseat said valve, thus pervmitting the use o f` agrelatively lowlifting pressurewith a comparatively high submergence pressure.

A still further `object .of the invention is to vention will behereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of thefollowing specification and by reference to the accompanying drawings,in which an example of the invention is shown, and wherein:

Figure 1 is a vertical sectional view showing an apparatus constructedin accordance with the.

invention installed in a well casing,

Figure 2 is an enlarged detail sectional view through the valve andnipple,

Figure 3 is an enlarged horizontal cross-sectional view taken on theline 3-3 of Figure 2,

Figure 4 is an enlarged horizontalcross-sectional view taken on the line4`4 of Figure 2,

Figure 5 is a view similar to Figure 1 showing `a modified structurebuilt in accordance with the invention,

Figure 6 is an enlarged sectional detail through the nipple and valveelements,

Figure 7 is an enlarged horizontal cross-sectional view taken on theline 1--1 of Figure 6,

Figure 8 isan enlarged horizontal cross-sectional view taken on the line8-8 of Figure 6,

Figure 9 is a vertical sectional view of another form of the invention,

Figure 10 is a cross-sectional view taken on the line III-I0 of Figure9, and

Figure 11 is a cross-sectional view taken on the line II-II of Figure 9.

In the drawings the numeral I0 designates a string of tubing or wellcasing. For the sake of clarity in the explanation the string I0 will bereferred to as a casing in order-to distinguish it from a smaller stringof tubing I2, which is mounted therein; but it is to be understood thatthe string I0 may be either the well casing or l the well tubing, whichis usually disposed in the well casing. An upper nipple I3 is connectedto the lower end of the tubing I2 by a collar or coupling I5, while thelower end of thenipple is screwed into the upper end of a valve housingI1. The housing is made integral with and has its outer surfacesubstantially flush with a sleeve I1 depending therefrom. The upper endof a lower nipple 30 is screwed into the lower end of the sleeve.

It will be observed that the elements I2, I5, I3,v I1, I1 and 30 areeach less in diameter than the internal diameter or bore of the casingI0, whereby an u prighi; annular space is maintained between saidelements and the casing. This space constitutes a reservoir or owingchannel for the air or gas, which is used as an elevating or flowingagent. The compressed air or gas which is utilized to elevate theinfluent will be hereinafter referred to as the lifting fluid. In ordervto seal olf the bottom of this channel or reservoir and prevent theinfluent or oil and gas mixture, or the fluids-flowing from the wellsands, from entering said channel, the lower nipple 30 is provided witha reduced shank 30- and inverted flexible packing cups 3I are suitablyfastened onthis shank so as to be expanded by .an upward pressure. The.nipple has an axial bore 32 which forms an entrant passage forthefluids flowing from the oil and gas sands. y' The valve housing I1 hasan inclined annular seat 20, which is preferably ground, and whichthrough the ports I6.

terminates short of the nipple 30. This sleeve is disposedconcentrically within the sleeve I1 and is considerably less indiameter. By this arrangement, an annular passage or channel 26 isformed between the sleeves. A plug 29 screwed into the bottom of thesleeve 25 closes the same and thereby said sleeve provides a chamber 25.Ports 21 at the upper end of the sleeve 25 provide communication betweenthe passage 26 and the chamber 25. A duct 28 extends through the sleevesand provides communication between the casing and the chamber 25 for theadmission of the lifting fluid.

'Ihe valve I8 has a reduced stem 22 which extends axially down thechamber 25 and terminates short of the plug 29. Above the duct 28 -acollar 2l is made integral with the stem. A

flexible packing cup I9, mounted on the stem, receives the collar and isheld in position by a washer 23 and jam nuts 24 mounted on the lower endof the stem. The cup I9 has a snug sliding fit in the' chamber 25 andprevents byv passing of the uids entering through the ports 21 and theduct 28. It will be obvious that the influent flowing from the bore 32by way of the passage 26 through the ports 21 into the chamber 25 willexert a downward pressure against the cup I9 and an upward pressureagainst the shoulder 26 of the valve; while the lifting fluid flowingthrough the duct 28 into the lower portion of the chamber 25 will exertan upward pressure against the cup I9. l

In the nipple I3 above the valve housing I'I,

'I mount a plurality of removable plugs III, each able pressure drop inthe fluid passing into the chamber 25. By this arrangement, the pressureacting upwardly against the cup I9 and tending to open the valve I8will, under normal flowing conditions, always be slightly greater thanthe lifting pressure exerted downwardly on said valve by reason of thefluid introduced through the ports I6.

In describing the operation, it may be stated that the area of theshoulder 20 of the valve,

which is exposed to the submergence pressure, is less than the area ofthe chamber 25. 'Therefore, the valve would be closed because of' thegreater pressure exerted on the cup I9. However, in order to induceflowing of the well, the pressure of the lifting fluid entering throughthe duct 28 is built up so as to overcome the submergence pressure andlift the cup I9, whereby the`valve I8 is opened.v When the' valve isopened the influent will flow upwardly through the housing I1 and willbe picked up by the jets or streams of lifting fluid entering the nippleI3 The combined submergence and lifting pressures will maintain the flowof the well.

If at any time during the flowing, the flowing pressure of the fluidspassing upwardly above the valve I8 should too closely approach thepressure of the lifting fluid, due to slippage of the fluids in thetubing string I2, or the too rapid rate of entrance of the influent, thevalve I8 will be seated and prevent further entrance of oil, orpartially so, until these conditions have been overcome. Where slippagetakes place,` the downward pressure on the valvewill be so Ygreat as toclose it, and where the .entrance-is -too rapid, the downward pressureon th'e`cup I9 will become so great as to close the valve. The column ofoil standing in the tubing will exert a downward pressure or weight onthe inlet valve.

This weight will be applied, particularly wherev there is slippage ofthe oil. Whenever the weight of the column of oil overcomes the flowingpressure of the oil passing the inlet valve, the weight/ of said columnwill close the valve,

When the valve has been closed by slippage or an increased downwardpressure thereon, it will remain closed until the excess pressure abovehas been overcome, by reason of the lifting fluid entering the column ofinfluent through the ports I6 and reducing the weight of such column.

When this occurs, the lifting fluid entering through the duct 28 willact against the cup I9 and open the valve. It will be obvious that theamount of influent which may pass the valve I8 is always commensuratewith the amount of en-V ergy or lifting force, in the form of air orgas,`

I fluid vor byv closing the valve controlling the discharge of oil andgas from the tubing. When the flow is stopped by cutting off the supplyof lifting fluid, the lifting pressure which is effective through theduct 28 and against the underside of the cup I9, will drop rapidly sothat the pressure differential of the submergence pressure acting inconjunction with the flowing `pressure will seat the valve I8. It ishere pointf ed out that the valve I8 is of a type which will or onehundred pounds.

act comparatively slowly so that the opening and closing will not besudden, but rather gradual.

The wings I8a have a snug sliding fit in the housing I1 and tend toretard the action of the valve. They also prevent whirling of saidvalve. Ifthe flow is terminated by closing the tubing at its dischargeend, the input pressure of the lifting fluid will stilll be effective.This fluid entering through the ports I6 will build up pressure in thecolumn of fluid in the tubing and this pressure being exerted downwardlyaswell as upwardly, will force the valve I 8 to its seat. In bothinstances the valve will remain closed until lifting fluid is againadmitted to the casing or the discharge valve of the tubing is opened.

Where the flow has been stopped by cutting off y the supply of liftingfluid it will be necessary to in the'chamber 25, but must also lift thevalve against the weightV of the fluid trapped thereabove. However, aslifting fluid will be admitted through the portsIG, the weight of thetrapped fluid will be lightened, thus assuring opening of the valve atthe proper'time.

When the flow has been stopped by-closing the tubing discharge valve, itwill be resumed when said valve is opened, whereby the pressure fluidflowing through the ports I6 into the tubing will lighten the load onthe valve I8, whereby the effective pressure under the cup I9 may buildup sufliciently to open the valve. It is pointed out that in neithercase is it necessary to employ a kickoff or excessive pressure ofV twohundred or three hundred pounds, and the same working elements whichmaintain flow are utilized to start flow when the same has been stopped.

It is obvious that the valve I8 acts as a regulator and variations inIthe pressures will move the valve up and down with relation to its seat2U. By this arrangement the entrance or rate of entry of the influentinto the tubing is regulated. Under excessive conditions the valve willbe entirely closed, but under merely abnormal conditions it may be onlypartially closed, thus cutting down the passage of theinfluent throughthe seat. Where 'the diameter of the seat is less than that of the bore32, said seat will function as a bottom hole choke or flow restrictionopening. However, the valve I8 co-acting with -the seat acts more asaregulator than it does as a true choke. The elements I5, I3, I 1, I1'and 30, being tubular conductors, are considered a part of the tubing;and the term tubing is used herein in such broad sen-sc as to include.these tubular conductors.

With the apparatus which has been described, the pressure of the liftingfluid in the space between the casing Illand the tubing I2 is alwaysless than the submergence or bottom hole pressure which acts upwardlyagainst the shoulder 20T and downwardlyvagainst the cup I9 in thechamber 25. It is possible under somev conditions that the flowingpressure above the valve I8 may become greater than the submergencepressure, whereby the valve I8 would remain open and a downward pressurewould be exerted against the oil sands which would be detrimental.

It is desirableto so proportion and operate the elements that the valveI8 will close before the flow pressure above said Valve equals thepressure of the lifting fluid discharged into the tubing through theports I6. For preventing downward or back pressure reaching the oilsands, I provide a drop valve 33, as is shown in Figures 5, 6 and 8.This Valve has guide wings 34 and is mounted in the upper end of thenipple 30; It is ground to fit a seat 35 at the upper end of the bore32. It is obvious that the upper surface of the valve 33, which isexposed to the downward pressure, is greater than thcl'area which isexposed to the submergence pressure inthe bore 32. Therefore, the valvewill open and close according to whichever pressure dominates.

As has been before stated, the ports I6 are of such size as to cause apre-determined pressure drop in the streams of airor gas introducedtherethrough into the influent flowing upwardly in' from the upper endof the tubing, the flowing pressure in the tubing would rapidly drop. Asbefore stated, should the combined lifting pressure and flowing pressureabove the valve 33 become greater than the submergence pressure of theinfluent, then said valve will be seated. If the upper effectivepressure area of the valve 33 is twice that of its lower effectivepressure area, then the valve will remain closed and no more fluid canenter the tubing until enough fluid already in the-tubing has beendischarged-from the upper end to cause thepressure above the valve 33 todrop to one-half of that beneath it. It is obvious that this or asimilar arrangement will give a margin of safety, whereby the valve33.wil1 remain closed until a. dominating submergence pressure isassured.

In Figures and 6,I have shown an additional cup 36 mounted on the stem22 and spaced from the cup i9 by a washer 31. The cup 36 is invertedwith relation to the cup I9 and is supported on a collar 23', which isheld in place by the nuts 24. The purpose of this additional cup ismerely to guard against a possible by-passing of the fluids in thechamber 25 and is n ot essential to the invention.

In Figures 5, 6 and '7, I have shown plugs i4' instead of the plugs i4provided with counterbores 4l) extending from the ports i6' and openinginto the tubing. Ball valves 38 are retained in the counterbores by pins39. These balls form checks and seat against the inner ends of the portsI6' so as to prevent a dominating fluid pressure in the tubing fromescaping-into the casing I0, particularly where the lifting fluid supplyhas been cut olf.

n Figures 9, and 11, I havevshown another form wherein the tubing l2becomes the conductor for the lifting lfluid and the casing or tubing l0becomes the conductor for the influent. A nipple 45 having an axial bore46 is disposed in the casing and 'packed off by inverted cups 41 mountedon the nipple in the usual way. The nipple has a reduced screw-threadedpin 48 at its upper end, which is screwed into the lower end of a bellhousing 49. The housing has a reduced neck 50 at its upper end, which isconnected with the tubing ll2 by a collar 5I;

T'he pin 48 of the nipple has a reduced bore 52 provided with aninclined valve seat 53 at its lower end for receiving a tapered valve54. The

valve is provided with radial guide wings 55 having a sliding flt in thebore 52. It is pointed out that the effective pressure area of the valve54 below its seat, is greater ythan its effective pressure area aboveits so that the submergence pressure may dominate and close the valveupwardly against its seat. The bell housing has a cross partition 56provided with ports 51. Be-l tween this partition and the pin 48 apressure chamber 58 is formed in said housing. The housing has outletsor ports 59 just above the pin 48. The valve 54 has a stem 60 extendingupwardly v from its wings 55 and passing freely through a Awhereby itexerts a' downward pressure on the cup 63. The pressure of the column offluid in the casing l0 is exerted against the underside of the cupthrough the ports 59 when the valve 54 is closed. When said valve isopened the flowing pressure is exerted against the underside of y fluidpressure which will open the valve 54 will be considerably less than thesubmergence pressure. In this, as well as in the other forms, it isessential to maintain a lifting energy or capacity which is greater thanthe load to be lifted. The underside of the cup 63 offers a greaterpressure area than the upper side of the valve 54 and consequentlywhenever the downward pressure of the influent approaches the slippagestage, a pressure differential is built up in the chamber 58, whichtends to lift the cup 63 and close the valve. The valve can only beopened when the lifting pressure exerted downwardly on said cup throughthe ports 51 becomes greater than the differential in said chamber. Itisnot believed necessary to discuss the operation any further. as the sameprinciples which have been hereto'- fore explained are present in thisform. While the lifting fluid has been described a air or gas suppliedartificially from the surface, it is pointed out that natural gas maybeemployed. The cups3i in Figure 1 pack olf the casing I0 and by closingthe upper end of the casing a storage chamber is formed between thetubing and the casing. It is obvious that if the casing I0 was disposedin a larger casing (not shown) and the gas from below the packersby-passed into the storage-space, a natural lifting fluid would beprovided. If this fluid did not provide sulllcient pressure energy, itcould be augmented by artificial pressure from -the surface.

The description which has been given recites more or less detail of aparticular embodiment of the invention, which is set forth as new 'anduseful; however,.I desire it understood that the ducing and reducing thepressure ofa lifting fluid into the tubing for lifting the influentflowing up the tubing, means for controlling the admission of theinfluent, means for operating the controlling means by the liftingfluid, and means for operating the controlling means by the submergencepressure of the influent in opposition to the lifting fluid.

2'. A well flowing apparatus comprising, a tubing having an influentinlet and an inlet for admitting a lifting fluid, a valve locatedbetween the inlets for controlling the passage of the influent, andmeans for opening and closing said valve having one side exposed to thepressure of the lifting fluid-and its opposite side exposed to thesubmergence pressure of the influent.

3. A well flowing apparatus comprising, a tub- 2,002,791 ing having aninfluent imei and a iiftingy fluid inlet thereabove, and means betweenthe inlets exposed to the opposing pressures of theV fluids foroperation thereby for controlling the passage of the influent, wherebythe flowing pressure of the influent above said means is prevented fromequaling the pressure of the lifting fluid flowing through its inlet.

4. A well flowing apparatus comprising, a tubing having an influentinlet and -a lifting fluid inlet thereabove for admitting a liftingfluid to the influent flowing upward in the tubing, a. valve locatedbetween the inlets of thetubing for controlling entry of the influentinto the tubing, said valve being 'overbala'nced with respect to thesubmergence pressure of the influent, and operating means for said valveexposed to the opposite pressures of the lifting fluid and the influent,said valve being controlled in its movement relative to its seat by thepressure differentials of the influent and` the lifting fluid, wherebythe quantity of influent passing the valve is controlled.

5. A well flowing apparatus comprising, atubing having an influent inletand a. lifting fluid inlet thereabove for admitting a lifting fluid tothe influent flowing upward in the tubing, a valve located between theinlets of the tubing for controlling entry of the influent into thetubing, a chamber below the valve open thereto and having an influentinlet and a lifting fluid inlet, and operating means for the valvehaving a sliding flt in'the chamber between the inlets thereof.

'6. A well flowing apparatus comprising, Aa

string of tubing having an influent inlet, a valve e controlling theadmission of and passage of the influent upwardly in the tubing, meansfor constantly admitting a lifting fluid under pressure to the tubingabove the valve, the valve having opposed unequal working surfacesexposed to the submergence pressure of the influent and a third workingsurface exposed to the lifting fluid, the working surfaces of the valvebeing so disposed that the applied pressure differentials of thesubmergence pressure act to seatthe valve to reduce the entry of theinfluent while the applied pressure of the lifting fluid acts to openthe valve and increase the admission of the influent. e l

7. A well flowing apparatusl comprising,` a string of tubing having aninfluent inlet, means for separating and constantly admitting a liftingfluid under pressure to the tubing above the inlet, and means operatedby the pressure differentials ofthe fluids for cutting off the admissionof the influent before the flow pressure equals the input pressure ofthe lifting fluid.

8. A well flowing apparatus comprising, a string of tubing having aninfluent inlet, means for constantly introducing a lifting fluid .underpressure into'the tubing above the inuent inlet at a reduced pressure,and means operated by the pressure differentials of the fluids forcontrolling the -admission of the influent to the tubing.

9. A well flowing apparatus comprising, a tubular valve `housing havinga valve seat, a valve slidable in`the housing and engaging the seatthereof, a tubular conductor connected to the upper end of the housingand having inlet ports above the valve, achamber below the valve seat ofthe housing connected therewith and having an influent inlet, a pistonslidable in the chamber, whereby the influentjis received between thevalve and said pistn), means for admittingta. lifting fluid underpressure to the chamber on the opposite side of the piston, and d meansfor packing 'off the casing below the last named inleti v 10. A wellflowing apparatus comprising, a string of tubing having an influentinlet, a valve `controlling the admission of and passage of the influentupwardly in the tubing, means for constantly Vadmitting a lifting fluidunder pressure to the tubing above the valve, the valve having opposedunequal working surfaces exposed to the submergence pressure of theinfluent and a third working surface exposed to the lifting fluid, the

working surface of the valve being sodisposed that the applied pressuredifferentials of the submergence pressure act to seat the valve toreduce the entry of the influent while the applied pressure of thelifting fluid acts to open the valve and increase the admission of theinfluent, and means for cutting off the flow of the influent when thevalve remains open and the flowing pressure bypasses the samedownwardly.

1l.A A well flowing apparatus comprising, a tubing having an influentinlet, means for introducing andreducing the pressure of a lifting fluidinto the tubing for lifting the influent flowing up the. tubing, meansfor controlling the admission of the influent, means for operating thecontrolling means for the influent, means for operating the controllingmeans by the submergence pressure of the influent in opposition to thelifting fluid, and means for preventing a back flow of the reducedpressure lifting fluid at its point of inlet.

12. The method of operating oil wells having tubing therein providedwith a. control valve at its lower end which consists, inl admitting anoil and gas influent through said valve located in the lower portion ofsaid tubing, admitting lifting fluid into the tubing above said valve toelevate the influent, reducing the rate of admission of the influentthrough said valve when the pressure within the tubing above said valveexceeds a pre-determined proportion of the lifting fluid pressure,continuing the introduction of lifting fluid until the pressure withinthe tubing above said valve has been lowered to a pre-determinedproportion of the lifting fluid pressure, and then increasing the rateof influent admission through said valve. t

1'3. The method of operating oil wells having tubing therein providedwith a control valve at its lower end which consists, in admitting anoil and gas influent through said valve located in the lower portion ofsaid tubing, admitting a lifting fluid under` pressure into the tubingabove the valve to elevate the influent, closing said valve to reducethe rate of influent admission when f the pressure within the tubingabove said'valve exceeds a pre-determined lifting fluid pressure,maintaining said valve closed until the ratio of the pressure of thefluid within thev tubing above said valve to the lifting fluid pressurehas been lowered to a pre-determined extent, thenopening said valve toincrease the rate ofinfluent admission when said ratio has been loweredto a pre-determined extent. Y

14. The method of operating oil. wells having tubing therein providedwith a control valve at its lower end which consists, in controlling therate of admission of oil and gas into the tubing, closing the controlvalve in the lower portion of the tubing to cut off the flow ofinfluent, admitting a liftingfluid under pressure into the tubing abovethe valve to elevate theinfluent previously entering said tubing, andopening said valve to admit inuent fluids only when the pressure withinthe tubing above the valve is less than the pressure ofthe liftingfluid.

15. The method of operating oil wells having tubing therein providedwith a control valve at its lower end which consists, in admitting anoil and gas influent into the well tubing through said valve located inthe lower portion of said tubing, admitting a lifting fluid into thetubing above the valve to elevate the influent, and regulating the rateof influent admission by said valve so as to maintain a, relativelyconstant ratio between the pressure within the tubing immediately abovethe valve and the pressure of the lifting fluid'.

16. A well flowing apparatus comprising, a

tubing for conveying a'lifting fluid under pressure down into the wellcasing, avalve seat at the lower end of the tubing, an influent inletbelow the valve seat, the tubing having an outlet above the seat, avalve engaging the under side of the seat, and a pressure operateddevice in the tubing engaging the valve for opening the same'against"the submergence pressure below said valve and for closing said valvewhen the submergence pressure and the flowing pressure exceeds thelifting pressure. A

17. The method of operating oil wells `having tubing therein andprovided with a control valve at the lower portion thereof whichconsists, in admitting through saidl valve an oil and gas influent to beelevated into the tubing, introducing a lifting fluid under pressureinto the tubing at a 4point above the entrance of the influent, andregulating the entry of the influent into the tubing through said valveby providing a pressure differential pressure against the combinedsubmergence and differential pressures.

18. The method of operating oil wells .having tubing therein providedwith a control valve at its lower end which consists, in controlling therate of. admission of oil and gas into the tubing through said valve,,closing the control valve in the lower portion of the tubing to cut offthe flow of influent, admitting a lifting fluid under pressure into thetubing above the valve to elevate the influent previously entering saidtubing, and opening said valve to admit influent fluids only when thepressure within the tubing above the valve is less than the pressure ofthe lifting fluid.l

19. The method'of operating oil wells having' tubing therein providedwith a control `valve, at its lower end which consists, in admitting anoil influent to the tubing through said valve, admitting a lifting fluidunder pressure to .the tubing to elevate the oil influent, andcontrolling through said valve the rate of admission of the oil influentinto the tubing by applying the pressure of the lifting fluid directlyagainst the flowing pressure of theoil influent.

20. The method of operating oil wells having tubing therein providedwith a control valve at its lower end which consists, in admitting anoil 'influent to the tubing through said valve, admitting a liftingfluid under pressure to the tubing to elevate the oil influent,controlling through said valve the rate of admission of the oilinfluentinto the tubing by applying the pressure of the lifting fluiddirectly against the flowing pressure of the oil influent, and cuttingoff or reducing vrthrough said valve the admission of the oil influentwhen the quantity of the same becomes Athe tubing by applying theVflowing the same upwardly nearly equal to the lifting energy of thelifting fluid.

21. The method of operating oil wells having tubing therein providedwith a control valve at its lower end which consists, in admitting anoil influent to the tubing through said valve, intro.

ducing a lifting fluid under pressure into the flowing influent aboveits point of entrance into the tubing, cutting off the admission of theinfluent through said valve after a predetermined amount thereof hasbeen admitted to the tubing, continuing the admission of the liftingfluid until the excess of influent has been discharged from the tubing,and then resuming admission of the influent.

22. The method of operating oil wells having tubing therein providedwith a control valve at its lower end which consists, in admitting anoil influent under pressure through said valve to thev tubing, reducingthe pressure of the lifting fluid' and introducing it into the influentfor flowing the same upwardly in the tubing, maintaining the flow of theinfluent into the tubing through said valve by a dominant pressure ofthe lifting fluid outside of the influent, and controlling the admissionof the influent through said valve to pressure of the lifting fluidagainst the flowing pressure of the influent. 23. The method ofoperatingloil wells having tubing therein provided with a control valveat' its lower end which consists, in admitting an oil influent underpressure through said valve to the tubing, reducing the pressure of thelifting fluid and introducing it into the influent for flowing the sameupwardly in the tubing, maintaining the flow of the influent into thetubing through said valve by a dominant pressure of the lifting fluidoutside of the influent, and cutting off the admission of the influentthrough said valve to the tubing when the flowing pressure of theinfluent acting downwardly exceeds the submergence pressure of theinfluent. 24. The method of operating'foil wells having tubing thereinprovided with a control valve at its lower end which consists, inadmitting an oil influent under pressure through said valve to thetubing, reducing the pressure of the lifting fluid and introducing vitinto the influent for influent into the tubing through said valve by adominant pressure of the lifting fluid outside of the influent, andcutting off the admission of the influentY through said valve when theweight of the influent flowing up the tubing exceeds the submergencepressure of the influent.

25. 'Ihe method of operating oil wells having tubing therein providedwith a control valve at taining the flow of the in the tubing, main.

its lower end which consists, in admitting through said valve an oilinfluent to be elevated into the tubing, constantly introducing into thetubing at a point above the entrance of the influent a liftingiluidunder pressure, and regulating the rate of entry of the influent throughsaid valve into the tubing by providing a pressure differential in thesubmergence pressure of the influent and applying the pressure of thelifting fluid against the combined flowing and differential pressures.

HERBERT C. OTIS.

